1. Field of the Invention
The present invention relates in general to idling speed control systems of an internal combustion engine, and more particularly to the idling speed control systems of a type which can keep the idling driveability of the engine well even when a certain load of an auxiliary device is applied to the output of the engine.
2. Description of the Prior Art
For keeping the idling driveability of an engine in a satisfied level even when a load of an auxiliary device, such as air conditioner, power steering pump or the like, is applied to the output of the engine, various control systems have been hitherto proposed and put into practical use. Usually, in such control systems, the amount of air fed to the engine is increased upon sensing the load. One of these control systems is disclosed in Japanese Patent First Provisional Publication 54-76723. That is, in the measure of this publication, when, with the engine being under idling, an air conditioner is turned ON, the idling speed of the engine is increased to a target value by increasing the amount of air fed to the engine, the target value being looked up from a map. With that measure, undesired engine stop and/or performance deficiency of the air conditioner is suppressed.